Obesity refers to a body weight that exceeds the body's skeletal and physical standards. One well recognized parameter used to measure obesity is not directly the weight but the Body Mass Index (BMI) because it takes into account patient height: BMI is calculated by dividing weight by height squared and is expressed in kg/m2.
Obesity is usually defined as a BMI of 30 kg/m2 or greater, and is further broken down into Class I (BMI of 30-34.9 kg/m2), Class II (BMI of 35-39.9 kg/m2) also called severe obesity, and Class III (BMI of 40 kg/m2 or greater), also called extreme obesity. Obesity is considered “morbid” when the BMI is over 40 (extreme obesity) or the BMI is over 35 (severe obesity) and serious comorbidities are present.
Obesity is well recognized as a serious health problem, and is associated with numerous health complications, ranging from non-fatal conditions to life threatening chronic diseases. According to the World Health Organization, the non-fatal, but debilitating health problems associated with obesity include respiratory difficulties, chronic musculoskeletal problems, skin problems and infertility. Life-threatening problems fall into four main areas: cardiovascular disease problems; conditions associated with insulin resistance such as type 2 diabetes; certain types of cancers, especially the hormonally related and large bowel cancers; and gallbladder disease. Beyond these physiological problems, obesity has also psychological consequences, ranging from lowered self-esteem to clinical depression.
Surgical intervention generally is the treatment of choice for patients afflicted with morbid obesity. Such intervention not only mitigates the myriad health problems arising from overweight, but may reduce the risk of early death of the patient. Left untreated, morbid obesity may reduce a patient's life expectancy by ten to fifteen years.
Morbidly obese patients as a group are poorly adapted to attain sustainable long-term weight loss using non-surgical approaches, such as strict diets combined with exercise and behavioral modification, even though such methods are acknowledged to be the safest. For this reason, there is a continuing need for direct intervention to provide effective, long-term treatments for morbid obesity.
Three main surgical procedures are currently in use: Roux-en-Y Gastric Bypass (“RYGB”), Vertical Banded Gastroplasty (“VBG”) and Adjustable Gastric Banding (“AGB”).
In RYGB a small stomach pouch is created and a Y-shaped section of the small intestine is attached to the pouch so that food bypasses the lower stomach, the duodenum and the first portion of the jejunum. The RYGB procedure is both restrictive, in that the small pouch limits food intake and malabsorptive, in that the bypass reduces the amount of calories and nutrients the body absorbs.
VBG employs a non-adjustable synthetic band and staples to create a small stomach pouch. AGB employs a constricting synthetic ring that is placed around the upper end of the stomach to create an artificial stoma within the stomach. The band is filled with saline solution and is connected to small reservoir/access-port located under the skin of the abdomen. The AGB band may be inflated, thereby reducing the size of the stoma, or deflated, thus enlarging the stoma, by puncturing the access-port with a needle and adding or removing saline solution. Both VBG and AGB are purely restrictive procedures, and have no malabsorptive effect.
An example of the AGB technique is described, for example, in U.S. Pat. No. 5,074,868 to Kuzmak. As described in that patent, a flexible band of elastomeric material is implanted around the stomach to form a closed loop defining a fixed pre-established diameter. The body of the flexible band includes an expandable chamber, which is linked via a tube to a subcutaneous injection port. Fluid may be introduced into the injection port using a syringe to add or remove fluid from the expandable chamber and thus vary the internal diameter of the band and the diameter of the stoma. In this way, expansion of the chamber, in combination with the pre-established and fixed diameter of the band, permits adjustment of the stoma diameter and thus regulation of the quantity of food ingested.
While the device described in the Kuzmak patent is capable of providing satisfactory results, it nevertheless-suffers from a number of drawbacks. The injection port is the source of many of the problems encountered with the hydraulic gastric bands, including infection, damage to the tube due to imprecise puncturing with the needle, discomfort to the patient created by the port and difficulty in locating the port (often necessitating the use of x-ray to determine the location and orientation of the port).
In addition, although the injection port makes it possible to make limited adjustments to the diameter of the ring without major surgical intervention, installation of the band may be accompanied by intolerance phenomena, such as vomiting. This drawback may arise from various causes, including too great a reduction in the diameter of the stoma, ineffective action of the band due to too great a stoma diameter, obstruction, infection or local or general inflammation.
Accordingly, it sometimes is necessary to re-operate, either to relieve the patient or to adjust or change the previously-implanted band. In such cases, the previously-implanted band must be cut and either removed or replaced, during operations that are difficult to carry out, difficult for the patient to tolerate and costly.
U.S. Pat. No. 5,938,669 to Klaiber et al. addresses some of the issues arising from use of an injection port, and describes a gastric band that is adjusted using a remote control in a non-invasive manner. The device includes a control box that is implanted in the body of the patient and coupled to the gastric band. The control box includes a battery-operated electric pump and valve that are coupled between an expandable chamber and a fluid reservoir. The control box also contains a radiofrequency transceiver and microprocessor, which are arranged to communicate with an external remote control to control operation of the pump to add or remove fluid from the reservoir to the expandable chamber, thereby selectively varying the diameter of the stoma opening. The external remote control is operated by a physician.
The device described in Klaiber presents an interesting and beneficial development for patients, but still suffers from a number of drawbacks. Implantation of that system's fluid reservoir into the body of the patient requires a delicate procedure, so as to avoid puncture and maintain watertightness. Likewise, the introduction of a battery within the patient's body confers an undesirable degree of fragility upon the system. For example, further surgical intervention is required to replace a depleted or leaking battery.
Several attempts to overcome drawbacks associated with hydraulically-actuated gastric bands, such as described in the Kuzmak and Klaiber patents, are known in the art. For example U.S. Pat. No. 6,547,801 to Dargent et al. describes a surgically implanted gastroplasty system having a flexible tractile element that engages a motor-driven notched pulling member. The motor is powered and controlled by an inductive circuit, so that the diameter of the ring may only be changed by operation of the external remote control.
Although the system described in the Dargent patent overcomes problems associated with injection ports used in previously-known hydraulically-actuated bands and with systems requiring implantable batteries, it too is expected to suffer from a number of drawbacks. For example, while Dargent states that the gearing of the pulling member is sufficient to prevent the band from unwinding in the unpowered state, the pulling member configuration still may permit the tractile element to “jump” or slip if the band is subjected to compression. Further, as shown in the drawings of that patent, when the band contracts, ripples form in the interior surface of the band that may cause inflammation or abrasion of the stomach.
In addition, it has been observed that within a few weeks of implantation of a gastroplasty band, fibrous tissue tends to overgrow and encapsulate the band. It is expected that, as in Dargent, where the exterior of the diameter of the band contracts upon actuation of the motor, such fibrous tissue may interfere with proper functioning of the device. Finally, while the band described in Dargent is flexible, it has no ability to stretch, for example, as may be needed to accommodate convulsive motions of the stomach, e.g., during vomiting, and consequently may lead to patient intolerance problems.
All of the foregoing surgical techniques involve major surgery and may give rise to severe complications. Recent developments have focused on the use of laparoscopic implantation of the gastric ring to minimize patient discomfort and recuperation time.
For example, U.S. Pat. No. 5,226,429 to Kuzmak describes a hydraulically-controlled gastric band that is configured to be implanted using laparoscopic techniques. The band is specially configured to be inserted through a laparoscopic cannula, and includes an injection port to control the degree of constriction imposed by the band. As previously noted, however, that band is expected to suffer from the same drawbacks as previously-known hydraulic gastric bands. In addition, that patent provides no teaching or suggestion as to how non-hydraulically controlled gastic bands could be configured for laparoscopic implantation. For example, the patent provides no teaching that would enable a clinician to adapt the non-hydraulic device described in Dargent for laparoscopic implantation.
In view of the foregoing, it would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that provides high precision in a degree of constriction imposed upon the organ or duct, without the drawbacks associated with the use of previously-known injection ports.
It further would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that maintains a desired level of constriction over an extended period using a gear-driven arrangement that may be implanted laparoscopically.
It also would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that is capable of accommodating occasional convulsive motions of the organ or duct.
It further would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that is telemetrically powered, so as to avoid the need for re-operation to replace or repair a defective or depleted energy source.
It still further would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that is telemetrically controlled, provides a high degree of safety, and reliably imposes a reproducible degree of constriction.
It also would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that maintains a constant exterior diameter, and is not rendered inoperative by tissue ingrowth or fibrous tissue encapsulation.
It further would be desirable to provide apparatus and methods for regulating functioning of a body organ or duct that may be non-invasively, safely and easily adjusted by a physician, without the need for radiographic imaging.